People invent false memories and confabulate all the time without even being "aware" of it. I wouldn't be surprised if the vast majority of "lies" that humans tell have no intentionality behind them.
Humans understand symbology of concepts as they relate to the real world. If I stole a cookie from the cookie jar, and someone asked if I took one, I would understand that saying "no" would mean that I was misrepresenting reality, and therefore lying.
LLMs have no idea what a cookie is, what taking one means, or that saying one thing and doing another implies a lie. It just sees lists of words and returns them in an order it thinks would be statistically likely to be a correct reply. It does not understand what words mean, what lying means, or have any idea how to classify anything as such. It just figures out that "did you take a cookie from the cookie jar" should return a series of words in an order like "yes, I took a cookie," or, "no I never took a cookie," depending on what sorts of responses it's trained on because those fit the patterns matched in the training data.
Essentially it's the Chinese room. There is no understanding or intentionality, and this behavior isn't comparable to humans thoughtlessly blurting out a lie. It's being incapable of comprehension of symbolic concepts in general, (at least thus far.)